JPS58167204A - Tire - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to tires, and more particularly to improved tread chimney turns for tires.

In the tire industry, special tread designs are selected and used alternately to develop specific tire performance characteristics. For example, tread patterns with good wet or snow traction are generally obtained at the expense of dry road handling, tread wear, rolling resistance, ride comfort, and noise levels; A treadmill turn with high durability and low rolling resistance is generally obtained at the expense of wet and snow traction. Conventionally, when improved wet traction or hydroplaning performance is desired, the volume of the void in the tire's tread area is increased by increasing the width of the groove or increasing the depth of the tread stop. It was simply increased by increasing the amount or by using both of these methods. However, increasing the volume of the void in this manner generally results in decreased performance with respect to dry traction, handling, tread wear, and/or increased noise levels.

Applicant has determined that acceptable levels of wet traction and no-hydroplaning properties of the tire are maintained while maintaining other properties such as rolling resistance, tread wear, noise levels, traction and handling. A special groove shape has been discovered in which the performance characteristics of the groove are maintained or improved.

FIG. 1 is a partial plan view of a train P12 for a pneumatic tire made according to the present invention. The tread groove shown in FIG. 1 is a pneumatic tire for a passenger car, in particular a pneumatic tire having a carcass structure of radial type construction and a belt reinforcing ply structure arranged in the tread area of the tire radially outward of the carcass structure. It is suitable as a pneumatic tire having a section. In the present invention, a radial type tire refers to a tire in which the cord of the carcass-reinforced ZORAI structure portion is arranged at an angle of about 75° to 90° with respect to the central circumferential center plane of the tire.

The tread includes a set of grooves 16 disposed around the entire circumference of the tire, which grooves extend over each of the axially opposed tread edges 14, 15 and axially extend a portion of the tread 12. extends across. The valley groove 16 is
In the footprint of the tire, the cross-sectional width is such that the grooves 16 do not come together on the tread surface. Preferably, the grooves 16 each have a substantially constant width. The centerline of groove 16 generally follows a portion of a path formed by an ellipse with axis A and axis B. Oval axis A is tire 1
0, and the ellipse axis B is substantially parallel to the central circumferential center plane, and any particular grooves 16 are located substantially perpendicular to the central circumferential center plane of the tread edge 14 from which they extend.
or located closely adjacent to 15.

The axis B of the groove 16 extends from the tread edge 14 or 15 a distance not greater than approximately 1/8 of the tread width TW. Preferably, axis B is located axially inward of the tread edge toward the central circumferential center plane cp. In the particular embodiment shown, axis B lies substantially along each tread edge thereof. The length L of axis B ranges from approximately 50% to 120% of the tread width TW, preferably approximately 70% to 100 inches, and in the particular embodiment shown, approximately 80% of the tread width. It is Chi. Here, the tread width of a tire is determined from the footprint of the tire when the tire is inflated to the design inflation pressure and a rated load is applied, and is the width of the tread 12 measured perpendicular to the central plane of the tire's circumference. This is called the maximum axial width. The groove 16 is at least 25% and preferably at least 35% of the width TW of the groove 16 in order to provide a continuous (-) circumferentially extending groove in the central part of the tire.
and extend axially across the trench rx2 a distance not greater than 75% of the tread width TW, more preferably not greater than 45 percent of the tread width TW. The axially innermost force point of the center line of No. 16 is arranged so as to extend continuously in the circumferential direction at a distance d of approximately 45 times the tread width TW from the tread edge where the groove begins, forming a lip of 3°. The ribs 30 contribute to reducing the noise level of the tire.

Circumferentially adjacent elliptical grooves 16 extending from the same tread edge are circumferentially spaced apart by a distance approximately equal to the length of axis B. Each elliptical groove 16 has a pair of ends opening at each tread edge 14.15]
Has 9.21. List 16 is from terminal part 19 to tren P
12 in a substantially continuous manner to the distal end 21 of the same groove. The register 16 includes a pair of bifurcated portions 20 extending from the open end 19.degree. 21 to a point 17 where they meet. The centerline of each branch 20 of the register 16 is substantially tangential to the centerline of the circumferentially adjacent branch 20 of the next groove 16, thereby substantially interconnecting adjacent branches 20. engage tangentially. Thus, circumferentially adjacent branch portions merge into a single groove having substantially the same longitudinal direction at or near the point where they meet. Having adjacent branch sections in close contact with each other helps to minimize any fluid turbulence that may occur in this area.

Providing the substantially elliptical grooves provides sufficient removal of water from the tire footprint by minimizing flow turbulence that occurs as fluid flows from the central portion of the tread to the tread edges. Accordingly, the Tren r pattern designed according to the present invention is capable of sufficiently removing fluids present within the footprint of the tire while also providing other performance characteristics such as dry traction, noise level and low rolling resistance.

A second set of elliptical grooves 22 is provided which comprises a list 22 that follows an elliptical path substantially the same as that followed by groove 16. Preferably, the axis C of the register 22 has a length LC, is parallel to the upper surface of the central cylinder of the tire, and is located substantially in the same plane as the axis B of the elliptical groove 16.

The axis of the register 22 is preferably substantially perpendicular to the central circumferential center plane of the tire 10 and parallel to the axis A of the groove 16. First and second sets of elliptical grooves 1
6.22 respectively combine to form a group of elliptical grooves. The oval-shaped grooves 16, 22 are substantially identical to each other, but are arranged at different positions circumferentially around the tire; The grooves 16 are arranged around the tire so that the axes A are substantially centered between the axes A of circumferentially adjacent grooves 16 . The present invention is not limited to such a transposed relationship. The axis line can also be located at any desired position between the axes A of circumferentially adjacent grooves 16. However, as mentioned above, it is preferred that the axes are located approximately in the center between adjacent axes A.

If desired, additional elliptical grooves can be added to the previously described grooves, in which case the axes of circumferentially adjacent grooves perpendicular to the central circumferential center plane of the tire are To minimize the concentration of empty areas around the circumference,
Preferably, they are arranged at substantially equal distances in the circumferential direction. Although two sets of elliptical grooves are shown in the embodiment of FIG. 1, only one set of grooves need be provided to practice the invention.

The tread 1/tread 12 has sufficient grooves such that the amount of void area present in the tread can handle water or fluid present in the tire's footprint. Accordingly, the tread 12 includes a sufficient number of grooves of a predetermined shape and configuration such that the gross-to-net ratio of the tread in the tire footprint is at least 50 inches and preferably not greater than 70%. . Here, the net ratio to the whole tread is the total area of the tread in contact with the road surface.
It is the ratio to the total footprint area of the tread. Tread 12
The inner grooves are arranged such that approximately 6" to 4 bifurcations of the elliptical grooves reside within the footprint of the tire from each tread edge.

The axis A of the register 16 extending from the tread 14 is arranged in a circle from the axis A of the groove 16 starting from the other tread edge 15 so as not to lie in the same radial plane, in order to minimize noise generation at the tread edge. Preferably, they are spaced apart in the circumferential direction, preferably with the axis A of the grooves 16 starting from the tread edge 14 being centered between the axes A of the grooves 16 starting from the tread edge 15.

In the embodiment shown in FIG. 1, the grooves 16.22 which also extend from the trend edge 14 are substantially identical to the grooves 16.22 which extend from the opposing tread edge 15. However, if desired, the grooves extending from the tread edge 14 can be used as shown in FIGS.
The grooves extending from the other tread edge may have a different size, shape or configuration as shown.

In the particular embodiment shown in FIG. 1, grooves 16 extending from the same tread edge each follow substantially the same elliptical path. However, if desired, the circumferentially adjacent grooves 16 can vary in size around the circumference of the tire.

In FIG. 4, two sets of oval shaped grooves are shown extending from each tread edge, where each set of grooves has two differently sized grooves 12'3, 125.

The branching portions of circumferentially adjacent grooves 123, 125 of each groove set are arranged to substantially abut each other in the area of the tread adjacent the tread edge. grooves 123, 125
have axes E and F, respectively, which extend substantially perpendicular to the central circumferential center plane of the tire and axes G and H, respectively, said axes G and H being substantially parallel to the central circumferential center plane; and is located in close proximity to the tread edge, such that axes G and H are each separated from the proximal tread edge by an axial distance not greater than approximately ]/8 of the tread width TW. When the two sets of grooves are arranged as shown in FIG. 4, the short axis H of the groove 125 is the large axis G.
It is approximately equal to 2/3 of This ensures an even distribution of voids in the shoulder area of the tread. If only one set of elliptical grooves with different alternating sizes is used, any desired size relationship between the different size grooves can be selected.

FIG. 5 shows three sets of alternating sized elliptical grooves. The length of the axis of the smaller elliptical groove parallel to the medium heat circumferential center plane CP of the tire is substantially equal to the axis of the larger elliptical groove parallel to the medium heat circumferential center plane CP of the tire. Equal to /2. Providing this relationship ensures an even distribution of voids in the shoulder area of the tread.

In FIG. 6, the elliptical grooves extending from the tread edge 214, if continuous, would extend from the opposite tread edge 214.
It intersects the groove starting at 15. The dashed line is the centerline of the elliptical groove that, if passed continuously, would intersect the elliptical groove starting from the opposite tread edge. The groove branching portion 230 follows an elliptical path from the tread edge to a termination point 233, said termination point being a distance D2 not less than approximately 30 inches of the tread width TW from the tread edge from which it begins to extend.
, this distance is at least 40 of the tread width TW.
% is preferable. The termination point 233 of each branch portion 230 is spaced from the top 235 of the elliptical path of the groove defined by the centerline by an axial distance D3 not greater than approximately 1/4 of the trench 1 width TW. Here, the top 235 of the elliptical path is
The point at which the elliptical path is farthest from the tread edge from which it begins to extend.From the terminal point 233 where the centerline of the groove branch portion 230 leaves the elliptical path, the groove 237 extends across the tread to the opposite tread edge. Each generally straight groove 237 is oriented at an angle α with the central circumferential center plane of the tire, which angle is not greater than approximately 60°. Let it be an angle.

FIG. 7 shows another variant embodiment of the invention in which several elliptical grooves 3 extend from one tread edge.
37 are connected by slotted grooves 340 that interlock with elliptical grooves originating from opposing tread edges and form an angle greater than approximately 60° with respect to the central circumferential center plane;
Preferably, the valley grooves 340 are substantially straight.

Although some representative embodiments and details have been described to explain the invention, it will be apparent to those skilled in the art that various modifications can be made without departing from the spirit or scope of the invention. .

For example, the repeat design cycle of the tread of a tire made in accordance with the present invention can be varied around the tire (known in the tire industry as the l-red design pitch).

Additionally, if desired, various grooves or grooves may be placed on the tread ξ turns as shown in FIG. You can also set it up.

[Brief explanation of drawings]

FIG. 1 shows a partial plan view of a portion of the tread of a tire made according to the invention, and FIGS. 2 to 7 show various alternative embodiments of the trend of tires made according to the invention. 12...Tread 14.15...Tread edge 16...Groove 17...Common point 19.21...End portion 20...Groove branch portion 22 ...Groove 30...Rip 123.125...Tread edge 230...Branch portion 233...Terminal point 235...Top 237...Groove 337... Groove 340... Groove Patent Applicant Zagutsu + F ear = Tire Andra, Groove, ξ Knee FIG, 1 FIG, 2 FIG, 6

Claims (1)

[Scope of Claims] 1. In a tire including a ground contact tread portion having a pair of axially opposing tread edges, the ground contact tread portion extends from each of the tread edges across the axial width of the tread P. a set of circumferentially adjacent grooves extending a distance of at least 25 inches in width, each set of grooves having a pair of distal ends and a pair of circumferentially spaced branch portions at the tread edge; one of said branching portions extending from each said end portion and meeting at a common point, each said groove extending along an axis generally perpendicular to said central circumferential center plane of said tire and said central circumferential center of said tire. following an elliptical path with a second axis substantially parallel to the plane, said second axis being spaced from the tread edge at which said groove begins to extend a distance not greater than one-eighth of the width of said tread portion; The circumferentially adjacent grooves are arranged substantially relative to the centerline of the branching portion of the next circumferentially adjacent groove in an area of said tread portion where the centerline of each branching portion is closely adjacent said tread edge. A tire characterized in that the tire is arranged around the tire so as to form a tangent to the tire. 2. A tire including a ground-contacting tread portion having a pair of axially opposed tread edges, wherein said ground-contacting tread extends from said tread edge a distance of at least 30 inches across the axial width of said tread. a set of extending circumferentially adjacent grooves, each groove of each groove set having a pair of distal ends and a pair of circumferentially spaced branching portions at the tread edge; one of the sections extends from each said distal end to a termination point, said diverging portion of said groove being substantially perpendicular to an axis generally perpendicular to the mid-circumferential center plane of the tire and substantially parallel to the mid-circumferential plane of the tire. generally follows a portion of an elliptical path with a second axis parallel to
the second axis of each said groove is spaced a distance not greater than one-eighth of the width of the tread portion from the tread edge where the groove begins, and the terminal point of each said branching portion is at the tread edge where the groove begins; said elliptical paths are furthest apart an axial distance of no greater than approximately one-eighth of the tread width, and said grooves are next in a region of the tread portion where each branch of said groove closely abuts a tread edge. A tire characterized in that the tire is arranged around the tire so as to be substantially tangential to branching portions of circumferentially adjacent grooves. 3. said tread portion having a second set of circumferentially adjacent grooves extending from at least one said tread edge across the axial width of said tread a distance of at least 25 inches of tread width; a groove having a pair of terminal ends and a pair of circumferentially spaced branching sections at the tread edge, one of the branching sections extending from each terminal section and generally perpendicular to the central circumferential center plane of the tire; one axis substantially parallel to the central circumferential center plane of the tire;
meeting at one common point with said groove generally following an elliptical shaped path having an axis, said second axis spaced a distance not greater than one-eighth of the width of said tread portion from the tread edge where said groove begins; Circumferentially adjacent grooves are arranged such that the centerline of the next circumferentially adjacent groove branch in an area of the train 1 portion where the centerline of each groove branch closely adjoins the tread edge; 2. A tire according to claim 1, wherein the tire is arranged around the tire so as to be substantially tangential to the tire. 4. said tread 1 section having a second set of circumferentially adjacent grooves extending across at least one said tread edge or across the axial width of said tread a distance of at least 30% of a tread width; , each said groove having a pair of distal ends and a pair of circumferentially spaced branching portions at said tread edge, each branching portion extending from one of said distal ends to one terminal end of said groove. The diverging portion generally follows an elliptical path having an axis generally perpendicular to the central circumferential center plane of the tire and a second axis substantially parallel to the central circumferential center plane of the tire; is spaced an axial distance not greater than approximately one-eighth of the tread width from the tread edge where the groove begins, and the terminal point of each branch portion is such that an elliptical path extends from the tread edge where the groove begins. The grooves are spaced an axial distance from the farthest apart point not greater than approximately ]/8 of the tread width, and the grooves are then circular in the area of the adjacent tread portion, with each branch of the groove approaching the tread edge. 5. The tire according to claim 2, wherein the tire is arranged around the tire so as to be substantially tangential to branching portions of circumferentially adjacent grooves.5. Claim 1 or 2, characterized in that it has a total-to-net ratio of %.
Tires listed in section. 6. The tire according to claim 1, wherein each groove of said first set of circumferentially adjacent grooves has substantially the same configuration. 7. A tire according to claim 1 or 2, characterized in that each groove of the first set of circumferentially adjacent grooves follows two differently sized elliptical paths. 86. Claim 1 or 8, characterized in that the axis parallel to the central circumferential center plane of the tire has a length in the range of approximately 50% to 160% of the width of the train 1 portion. Tire described in item 2. 9. The tire according to claim 1 or 2, wherein a continuous rib extending in the circumferential direction is formed between the first groove sets extending from each tread edge.